The Salt Lake Tribune reports the state Attorney General’s office made that argument in a brief filed in federal court Monday.

The brief is a response to a lawsuit from three gay couples challenging Utah’s voter-approved ban on same-sex marriage.

State attorneys argue all unmarried couples, including heterosexuals, are not constitutionally guaranteed rights enjoyed by married couples. They’ve also asked for a judge to dismiss the lawsuit.

The plaintiffs in the lawsuit said Utah’s constitutional amendment passed in 2004 denies gay and lesbian citizens the basic right to marriage as affirmed in the interracial marriage case Loving vs. Virginia.